Open sign



FIG. 1 is a perspective view of an open sign;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a right view thereof;

FIG. 5 is a left view thereof;

FIG. 6 is a top view thereof;

FIG. 7 is a bottom view thereof;

FIG. 8 is a rear perspective view thereof; and,

FIG. 9 is a front/bottom perspective view thereof.

The broken lines are included for the purpose of showing environmental structure and form no part of the claimed design. 

CLAIM The ornamental design for an open sign, as shown and described. 